Photographic materials are generally produced by forming at least one light-sensitive layer on a plastic film support.
Practically employed plastic films are cellulose polymers, such as triacetyl cellulose (hereafter abbreviated as TAC), and polyester polymers, such as polyethylene terephthalate (hereinafter abbreviated as PET).
In general, the forms of photographic materials are divided into sheets, such as X-ray films, plate making films, and cut films; and rolls, such as 35 mm or less wide color or black-and-white negative films for photographing packed in a patrone or a cartridge to be loaded into ordinary cameras.
A TAC film chiefly used as a support of roll films are characterized primarily by freedom from optical anisotropy and high transparency and secondarily by its property of eliminating curl after development processing. That is, since a TAC film exhibits relatively high water absorption as a plastic film in the nature of its molecular structure, the molecular chain once fixed to set the curl which occurred with time during storage in a roll form is made to flow and re-arranged upon absorption of water during development processing. As a result, the curl once set can be eliminated.
On the other hand, it is very likely that a TAC film also absorbs, because of its high water absorption, components of a processing solution which may have an adverse action in the subsequent processing steps or a drying step or even thereafter. For example, a color developing agent, if adsorbed in a support and is not completely washed away in a washing step, causes color stain with time. In case where a photographic material containing a coloring material, such as a dye, is continuously processed, a support may absorb the coloring material dissolved into a processing solution and is stained. These problems will become acuter with the decreasing rate of replenishment for consideration of environmental conservation and simplification of processing.
A less water-absorbing support, such as a PET film, gives rise to no such problems but, when used in a roll form, causes various problems due to the set curl, such as jamming or processing unevenness at the time of development, especially in mini lab.
Further, it has turned out that a photographic material using a support made of a poly(alkylene aromatic dicarboxylate) like a PET support tends to suffer changes in photographic performance with time after photographing up to development processing. This tendency is particularly conspicuous in cases where a poly(alkylene aromatic dicarboxylate) support is subjected to a heat treatment or a surface activation treatment, such as a corona discharge treatment, an ultraviolet treatment or a glow discharge treatment. It has therefore been demanded to make improvements in this point.